Yes, because either way they are a liar.

Yes, if someone tells you that they are a complete liar, I believe them, because one way or the other they are lying. If the person is lying about being a complete liar, they are lying about how often they do not tell the truth. If someone is telling the truth, then they are a complete liar. Either way, you're safe in believing them.

Yes. If someone tells me they are a complete liar, I will believe them.

Yes. If someone tells me they are a complete liar, I will believe them, because I don't see any reason for someone to lie about that. Also, regardless if its true, or not I will believe them. I am not interested in taking any chances with trusting people in toady's society.

Yes because words aren't concrete

If someone says they are a complete liar I will believe them. They are not saying they lying every time but they are saying they lie enough of the time to be considered a complete liar. There is no harm in taking their word about that, but there would be harm in ignoring what they are telling you.

I would have to, and I would also question their grammar.

I read long ago that if someone tells you something bad about themselves, or that they're not worth your time, or whatever, that it's likely true. And after growing up, getting married, getting divorced, and going on, I have to say that experiences has played that out to be true. However, a "complete" liar? That's kind of like being a little pregnant.

Not believing them makes logical sense

Let's say they are lying that they are a complete liar, then I wouldn't believe them. Lets say they are telling the truth, I still wouldn't believe them because what they did was tell the truth so not believing them makes sense either way. The must be lying, they can't be a complete liar and tell the truth.

No One Is A "Complete" Liar

A complete liar would be someone who never tells the truth, including when they tell you that they are a complete liar, which would mean that they aren't a complete liar. Aside from the semantic problem of the claim, it would be quite improbable that someone never told the truth. Try it for five minutes the next time that you have a conversation with someone. The mental energy required to continually lie would be quite draining, if not downright maddening! No one is a "complete" liar.

Think about it.

If a person tells you that they are a complete liar, do you belive them? Well, think about it. If a person is a complete liar, and they tell you that they are a liar, than they are either a liar telling the truth (which would't be lying) or a truth-teller lying. It's kind of complicated.

It's a paradox.

Sit back and think about it for a moment. If the person is a complete liar, they just told you the truth, so they are incorrect. If they are not a complete liar, then that statement is a lie. Nobody can ever say this and be correct. I suppose they can be mistaken, though!

No one is COMPLETE liar

The way I see it, no one is a complete liar. The old saying is true, through, everybody lies. That being said, there is always some truth coming out of some body's mouth. If someone were to look at me and call me a "complete liar" I would simply laugh if off.

Don't believe a confirmed liar

If someone tells you that they are a complete liar, you should not believe them. This is because of the fact that the person is logically deduced to be a liar either way. If the person is a complete liar, than they wouldn't tell you the truth about them being a liar, and if they aren't a complete liar, they are at least partially lying about how much they lie.